THE THYROID 17 



put to the test of experiment, and thereby fell short 

 of another great discovery : "It would be curious," 

 he writes, "to investigate if the macerated extract 

 of the thyroid, introduced into a cavity, or injected 

 into the rectum, has the same immunizing power." 



A repetition of Schiff's experiments by other in- 

 vestigators did not always corroborate Schiff's 

 findings. We have already suggested that an in- 

 complete knowledge of the parathyroids may have 

 been the cause of this. We may also add that not 

 only do animals of different species behave differ- 

 ently, but even animals of the same species do, pro- 

 vided there is a marked difference in age. 



Symptoms. Where the operation in an animal 

 has been successfully performed, some such symp- 

 toms as the following develop: The skin becomes 

 thick and dry; there is a loss of hair; the animal 

 shows a tendency towards obesity, particularly in 

 certain portions of the body; the muscles become 

 weak and the tissues renew themselves but slowly. 

 The blood is poor, in quality and quantity; the 

 temperature is below normal ; and the sexual func- 

 tions are interfered with. This interference with 

 the sexual glands is of uncommon interest, since 

 it suggests a close interrelationship between the 

 various hormones of the body an observation that 

 is strengthened every time a disease due to a hor- 

 monic disturbance is examined. The nervous sys- 

 tem is also attacked, dullness and general apathy 



